Electric relay



April 13, 1937.

E. J. BRANDER ELECTRIC RELAY Filed Feb. 8, 1935 0 m L h k) b m 0 \Z O OQQ B Q DQ k Patented Apr. 13, I937 PATENT OFFICE ELECTRIC RELAY Berti!Johan Brander, Stockholm, Sweden Application February 8, 1935, SerialNo. 5,648 g In Sweden February 23, 1934 15 Claims.

This invention relates to electric switching devices; and to circuitcontrolling elements for such switching devices.

It is well known to persons versed in the art that electric switchingdevices or relays used in modern telephone systems are, in most cases,prov vidcd with a plurality of contact springs which have toperformochanges in various circuits simultaneously. As the circuitsandtheir combinations vary with the systems, the size of the exchange, theconstruction of the selectors, etc., it is obvious that the circuitcontrolling elements of the relays must, in the various cases, becarried out withnumerous different combinations of the usual contactsfor closing, breaking or changing the circuits. Under thesecircumstances it is obviously impossible for the manufacturer of suchrelays to rationalize the production by standardizing the numerousdifferent relays with said contact sets are expensive to manufacture andcannot become a stock article, which of course would be desirable.

Attempts have been. made to improve the method of manufacture of suchrelays by adopting universal designs of various elements in such amanner that a plurality of distinct types of relays may be assembledfrom a common stock of piece parts and partially assembled units for thesets of contact springs, but, as far as applicant is aware, nosuggestion has been made heretofore to adopt universal designs ofcomplete spring piles for such relays, which of the present invention.This object is attained 5 by the use of very thin and flexible,non-pretensioned contact springs, the contact carrying ends ofwhich areforcedly moved or firmly supported and adapted to be set or rearrangedto different positions in relation to each other so as to form variouscontact combinations, while the solid back portion of the spring setremains a standardized unit;

Another object of the invention is to reduce the costs of manufacture ofthe relay by doing away with the usual method of adjusting the contactpressure by bending the various contact springs individually in order togive them the 1 proper tension. In place of this method of adjusting, acommon time-saving device is used for adjusting all the movable contactsprings simultaneously.

A further object of the invention is to give the contact springs acombined bending and twisting movement when closing a contact, in 55order to attain a certain rubbing or friction e1- types of spring sets.In consequence, complete is one of the objects feet on the contact, thusmaking it more reliable than the ordinary relay contact.

A further object of the invention is to increase the reliability of thecontacts of the springs by the introduction of a particular type of adouble contact. The double contact at present in use for the samepurpose, is established by splitting the spring ends and placing onecontact on each of the tongues thus formed. This arrangement howeverdoes not give sufilcient safety with regard to the closing of bothcontacts unless the springs are subjected to a'very careful examinationand adjustment, which means increased expenses and waste of time. Thedouble contact of the new type is arranged in such a manner that bothcontacts are automatically closed when two cooperating springs arepressed together, whereas no particular adjustment is required for thispurpose.

In the accompanying drawing is shown a relay designed according to theinvention.

Fig. l is an elevation of the relay,

Fig. 2 shows a plan view of same, and

Fig. 3 a cross section on a larger scale along the line III-III in Fig.1.

Figs. 4 and 5 show two diflerent types of contact springs used in thisrelay.

Referring to Figs. 1-3 the relay is'provided with an iron frame-orbracket a of the usual L- shape, at the front end of which an armature bis pivotally mounted in front of a coil c fixed in the usual manner atthe back end of the bracket a.

A set of, for instance, fourteen contact springs, l-l and ll-ll is madeup as a unit, mounted on a metal plate 1' which together with the springset, is fixed by means of screws on the back end of. the bracket a. Thecontact springs are insulated in-the usual manner by means of insulatingplates, or by a moulded block of insulating material. Above the contactsprings there is arranged'a special spring a, the tension of which isadjustable by means of a screw 1. The spring g is adjusted to give acertain pressure on the top end of a slide or movable member ,1 ofinsulating material, the lower end of which fits easily in a hole in theplate 1', while its top end is inserted in a hole in the spring 0. Thelower end of the slide 1 protrudes below the plate 1' and engages withthe horizontal part of the armature b, which is bent downwards throughan aperture in the bracket a. The reason for giving the armature crankthe curved shape, shown in Fig. 1, is to bring the point of contactbetween the crank and the slide ,1 down to the same level as the pivotof the armature, thereby reducing the friction at this point as far aspossible. The armature b may be pivoted in any suitable manner at thefront end of the bracket a. In the relay shown, thisisdonebymeansoftwobrasspinsflxedin the bracket a and fitting loosely in two correspondingholes in the armature b. A helicalspringshasitslnnerendflxedtothebrackets and its outerendto'theupperendofan adJust sprlngmaybeprovidedwithoneortwocontacm' In the relay. shownon the drawing as an example, one of said spring groupsthe right one inPig. 3-has each spring provided with a single contact point, while inthe other group-the left one in Fig. 3-each spring is provided with twocontact points.

- The movable contact springs 2, l, 8, i2, ll, It

aremountedclosetotheslidetandareattheir inner edge partly inserted inslots e, around the slide 1 in such a manner that they exactly followtheslide I when the. latter is moved upwards by the armature b, ordownwards by the spring a.

The groups of fixed and movable contact springs are placed laterally ashort distance apart, with the contact lugs of the respective groupsturned towards each other. The free ends of the fixed springs I, l, 8,I, II, II, II, II are held in their proper positions by having theirouter edge insertedin slots i at the circumference of two iixed posts I;of a synthetic molded resin or some other insulating material. The postsI: have their lower ends inserted in holes in the plate 1', while theirupper ends are inserted in corresponding openings, in two powerfulsprings 14. The springs a and u are preferably made in one piece andfixed by means of the same screws which are used for fixing the completeset of contact springs on the bracket 4 as shown in the drawing.

The plate 1' is provided with two adjusting screws for the purpose ofadjusting its height and thereby the height of the whole set of contactsprings in relation to the armature b. The plate 1' is further providedwith a slot 2:, which makes it possible to adJust the contact springsl-l to a diifere'nt height in relation to the springs il-l'l on theother side of the slide 1.

As already mentioned, the contact springs are arranged in such a mannerthat they may form various combinations of different contacts withoutany alteration in the building up of the spring pile. For this p rposethe slide f and the posts I: are provided with a greater number of slotsthan the number of contact springs, and by inserting the springs indifferent slots the ends of the springs may be set to difl'erent heightsin relation to its neighbouring springs. Thus, for instance, accordingto Fig. 3 the group of springs on the left side of the slide I have thesprings plscedin slotsoftheslideiandthe post k, which are suitable forone "change-over and two "make contacts. the former consisting of thesprings ii, l2, it and the latter of the springs I4, I! and l6, IIrespectively.

The group of springs on the right side of the slide 1, which consists ofthe same number of quite similar springs as the left group (with theexception that the springs are provided with single instead of doublecontacts). are arranged in a different way, the springs I and 0 havingchanged place in the slots of I and It, so that they together with thespring 1 form a so-called "double-make" contact. while the springs I, 2and 8 form a change-over" contact in the way as the contacts ii, I! andII in the previous case. The spring I is in this case left unused.

By the described arrangement of the contact springs it is pouible tomanufacture the spring sets in a few standardised units, for instancewith 2, I, II, II, II and 22 springs, and by inserting the spring endsin diii'erent slots in the slide I and the supporting posts I: a greatvariety of combinations of diifere'nt kinds of contacts may be producedFor instance, if a standard set of 22 contactspringsismountedonthisrelayintw'ogroupsof ll springs on each side of theslide I. each group of 11 springs may be arranged to give any one of thefollowing 7 diii'erent combinations:

(1) 1 "change-over and 4 "break" contacts.

(2) 4 make and 1 "change-over" contact.

(3) 3 "change-over", contacts.

(4) 2 change-over" and 2 make contacts.

(5) 2 change-over" and 2 "break" contacts.

(6) 2 "makes", 1 "change-over" and 2 break contacts.

(7) 1 "make", 1 "change-over" and 3 "break" contacts.

The manufacture of the spring sets in standardized units naturally willconsiderably reduce the costs of production. A further advantage is thatrelays of this kind. in existing plants (for instance in automatictelephone exchanges) easily may be altered, in case of alterations ofthe system or of the details of the diagrams.

The re-arrangement of the springs may in such cases be carried outwithout the aid of the manufacturer and at a small expense.

As mentioned above. the contact springs are made of very thin sheetmetal-preferably about one hundredth of an inch-which evidently is acondition for the setting of the springs in diilerent positions withoutnecessitating a special adiustment of the spring ends in each case. (Ibrthe sake of clearness, the contact springs are shown thicker in thedrawing than they actually are.)

A further condition for enabling a spring to make contact either withthe next spring above. or the next spring below, is of course that allthe springs are provided with contact points (of silver or the like) onboth sides, as shown in the drawing.

Theslots intheslidetand themstsltareiust only wide enough for thespringsto slip into them easily, but they do not allow any perceivable play orlag up or down. Thus the movable springs i, l, I, 1, II, II, II, II arebound to follow the slide 1 not only when the slide is raised during thepulling-up of the armature b, but also whenthearmatureisreleasedandthespringapresses the slide 1 down to its normalposition. Owing to the fact that the movable contact springs are made ofvery thin sheet metal, they have practically no tension of their own andcannot themselves give suiilcient pressure on the break" contacts.Therefore the necessary pressure on these contacts is furnished by thecommon adjusting spring g. Thus the pressure of the spring a on theslide, I will be evenly distributed on all the break" contacts when thearmature of the relay is in its normal position, and by adjusting thetension of the spring g by means of the set screw 1 the pressure may bevaried simultaneously on all the break contacts. It will be easilyunderstood. that much time and expense is saved by this method ofadjusting the relay contacts in place of the old-fashioned method ofbending each spring which does not give the proper pressure on itscontact.

With regard to the operation of the contact springs, the above-mentionedtorsion or twisting movement of the springs when pressed together takesplace on account of the springs being thin and of a narrow shape, andbecause the force causing the motion of a movable spring is applied toone of its edges (by means of the slide 1), while the contact is placednear the opposite edge. It is obvious that the same twisting movement isperformed by a cooperating fixed spring, because its support k reacts atthe outer edge of the spring, while the contact is located near itsopposite edge. The said twisting movement of two cooperating springsevidently causes a considerable rubbing or friction effect on thecontacts, which results in more reliable contacts or passages of currentthan in the usual arrangement of the springs.

As mentioned above, contact springs of the type shown in Fig. 4 may befurther improved by the arrangement of two contact points on eachspring. This improvement is illustrated in the group of contact springson the left side of the slide, Fig, 3, in which group all the springsare provided with double contacts, such as shown in Fig. 5.

When double contacts are used in relays, it is of course necessary toarrange the two contacts in such a manner that the force used forclosing them, is divided equally on both contacts. In hitherto knownrelays with double contact points one has tried to fulfill thisrequirement by splitting up the spring ends and placing one contact oneach of the branches or tongues. This arrangement has the drawback thata very careful and time-wasting adjustment of the two tongues of thespring is required, if both contacts shall work properly.

According to the present invention, a reliable function of bothcontacts, without any careful adjustment, is attainedby placing the twocontacts on two such points of the spring, which are distinctlydifferent with respect to resiliency, while two cooperating springshaving double contacts oi the kind just described, are arranged in suchpositions in relation to each other, that the more resilient contact ofone spring cooperates with the less resilient contact of the otherspring and vice versa. This result is preferably obtained by usingverythin and flexible sheet metal springs with a laterally projecting lug onone side, on which lug one of the contacts is placed, while the othercontact is placed on the main portion of the spring.

The improved arrangement of double contacts has the advantage that thecontact pressure, owing to the torsion of the cooperating springs, isautomatically and equally spread over both contact points.

It is to be observed that the slots i or e may of course be replaced byprojections on which the lateral edges of the contact springs rest.

What I claim is:-

l. A circuit controlling device comprising nonpretensioned movablecontact springs, stationary contact springs, an insulating memberengaging with and adapted to transmit motion in two opposite directionsto said movable contact springs, means operable by an external force formoving said insulating member in one direction, and a common springmeans engaging with said insulating member and acting thereon to urgesaid non-pretensioned movable contact springs towards their normalposition or in contact with stationary contact springs.

2. A circuit controlling device comprising a group of non-pretensionedmovable contact springs cooperating with a group of stationary contactsprings, a reciprocating insulating member provided with a plurality ofslots for said movable springs of substantially the same width as thethickness of said springs, whereby said insulating member moves saidmovable springs one way or the other without lag, and a commonpretensioned spring acting upon said insulating member to force saidmovable springs towards their normal positions or in contact withstationary contact springs.

3. A circuit controlling device as claimed in claim 2, whereinsupporting means is provided for mounting the back portions of saidmovable contact springs in predetermined fixed position while theirfront ends are adapted to be set in differently located slots of saidinsulating member, whereby said movable contact springs may form variouscontact combinations with said stationary contact springs withoutaltering the mounting of the back portions of said movable contactsprings in said supporting means.

4. A circuit controlling device as claimed in claim 2, whereinsupporting means is provided for mounting the back portions of saidstationary contact springs in predetermined flxedpositrons, incombination with an insulating support having a. plurality of slots inwhich said stationary contact springs may be received to position thecontact ends thereof with respect to said movable contact springs whilethe front ends of said stationary contact springs are adapted to be setin differently located slots in said insulating support, whereby saidstationary contact springs may form different contact combinations withsaid movable contact springs without altering the mounting of the backportions of said stationary contact springs in said supporting means.

5. A circuit controlling device as claimed in claim 2, whereinsupporting means is provided for mounting the back portions of saidmovable contact springs in predetermined fixed position,

and the number of slots of said insulating member for receiving themovable contact springs exceeds the number of movable contact springs,whereby the location of the several movable contact springs in the slotsof said insulating member may be varied to form different contactcombinations with said stationary contact springs without altering themounting of the back portions of said movable contact springs in saidsupporting means.

6. A circuit controlling device as claimed in claim 2, whereinsupporting means is provided for mounting the back portions of saidstationary contact springs in predetermined fixed positions, incombination with an insulating support having a plurality of slots inwhich said stationary contact springs may be received to position thecontact ends thereof with respect to said movable contact springs, thenumber of slots in said insulating support exceeding the number ofstationary contact springs, whereby the location oi'the severalstationary contact springs in the said slots may be varied to formdiiierent contact combinations with said movable contact springs withoutaltering the mounting of the said stationary contact springs in saidsupporting means.

7. A circuit controlling device as claimed in claim 2 in combinationwith supporting means for mounting the back portions of each of saidgroups of contact springs in fixed and uniformly spaced relation, and aninsulating support having slots to receive said stationary contactsprings to position the contact ends thereof with respect to saidmovable contact springs, the number of slots of said insulating memberand of said insulating support being each greater than the number ofassociated contact springs. whereby the location of the contact springsof each group in the associated spacing slots may be varied to formdiiferent contact combinations without altering the mounting of the saidgroups of contact springs in said supporting means.

8. In a circuit controlling device the combination of non-pretensionedmovable and non-pretensioned stationary contact springs made of thin andflexible sheet metal, a supporting unit for mounting the back portionsoi said springs in superposed and fixed position,-a reciprocatinginsulating member engaging with said movable contact springs by means oislots which tightly embrace one edge of the contact carrying ends ofsaid movable springs. a common pretensioned spring engaging with saidreciprocating member for restoring said non-pretensioned movable springsto normal position, and a fixed insulating member with slots forreceiving one edge of the stationary contact springs, one of saidinsulating members being provided with a number of spare slots forsetting or rearranging the contact ends of certain of said contactsprings to difierent positions and contact combinations.

9. A circuit controlling device of the type including movable andstationary contact springs each having two contacts working in parallel,and means for actuating the movable contact spring to bring the contactsthereof into and out of engagement with the two contacts of thestationary contact spring, characterized by the fact that the contactsof each contact spring are mounted thereon at points of substantiallydifferent resiliency, and the contact springs are relatively positionedto bring the more resilient contact of each contact spring intoengagement with the less resilient contact of the other contact spring.

10. A circuit controlling device as claimed in claim 9, wherein eachcontact spring is an elongated strip having a lug projecting laterallyfrom one side thereof at the contact end, the said contacts of eachspring are mounted respectively on the strip proper and on the lug; andthe two contact springs are laterally displaced with the ing of eachalined with the strip end of the other.

11. In a circuit controlling device, a pair of sets of normallynon-tensioned contact springs each including a group of movable contactsprings and a group of stationary contact springs, a common mountingmeans for retaining the back portions of the contact springs of eachgroup in fixed superposed position with the two groups of movablecontact springs laterally oii'set from and positioned between the groupsof stationary contact springs, a common reciprocating insulating memberhaving slots for snugly receiving edge portions of said movable contactsprings, spring means engaging said reciprocating insulating member forrestoring said movable contact springs to normal position, andinsulating means for positioning the contact portions of the severalstationary contact springs with respect to the co-operating movablecontact springs.

12. A circuit controlling device as claimed in claim 11. wherein saidinsulating means includes a stationary insulating member for each groupof stationary contact springs, said stationary insulating members havingslots for receiving edge portions of the stationary contact springs.

13. A circuit controlling device as claimed in claim 11, wherein saidinsulating means includes a stationary insulating member for each groupof stationary contact springs, said stationary insulating members havingslots for receiving edge portions of the stationary contact springs, andwherein at least one of said insulating members has spare slots inexcess of the number required to receive the corresponding contactsprings, whereby the relative location of the contact springs on aninsulating member having spare slots may be varied to form differentcontact combinations without altering the location of the back portionsof the contact springs on said common mounting means.

14. A circuit controlling device comprising a movable contact. springand a stationary contact spring each having a lug extending from oneside thereof, contacts carried by the said lugs, means supporting saidcontact springs in parallel oi!- set position with the said lugs thereofin overlapping relation, and means for actuating said movable contactspring to make and break contact between said contact springs.

15. A circuit controlling device comprising a pair of relatively movablecontact springs each having a lug extending from a side thereof, meanssupporting said springs in parallel oifset position with said lugsthereof in overlapping relation, a pair of contacts for each spring andlocated respectively on the lug and on the spring proper, the lugcontact of each contact spring being alined with the spring contact ofthe other spring, and means for eii'ecting relative movement of saidcontact springs to bring the alined contacts into and out of engagement.

BER'I'IL J ORAN BRANDER.

